diff options
| -rw-r--r-- | arch/riscv/Kconfig | 8 | ||||
| -rw-r--r-- | arch/riscv/include/asm/asm-prototypes.h | 4 | ||||
| -rw-r--r-- | arch/riscv/lib/Makefile | 6 | ||||
| -rw-r--r-- | arch/riscv/lib/riscv_v_helpers.c | 45 | ||||
| -rw-r--r-- | arch/riscv/lib/uaccess.S | 10 | ||||
| -rw-r--r-- | arch/riscv/lib/uaccess_vector.S | 53 |
6 files changed, 125 insertions, 1 deletions
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 95a2a06acc6a..3c5ba05e8a2d 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -525,6 +525,14 @@ config RISCV_ISA_V_DEFAULT_ENABLE If you don't know what to do here, say Y. +config RISCV_ISA_V_UCOPY_THRESHOLD + int "Threshold size for vectorized user copies" + depends on RISCV_ISA_V + default 768 + help + Prefer using vectorized copy_to_user()/copy_from_user() when the + workload size exceeds this value. + config TOOLCHAIN_HAS_ZBB bool default y diff --git a/arch/riscv/include/asm/asm-prototypes.h b/arch/riscv/include/asm/asm-prototypes.h index 6db1a9bbff4c..be438932f321 100644 --- a/arch/riscv/include/asm/asm-prototypes.h +++ b/arch/riscv/include/asm/asm-prototypes.h @@ -11,6 +11,10 @@ long long __ashlti3(long long a, int b); #ifdef CONFIG_RISCV_ISA_V +#ifdef CONFIG_MMU +asmlinkage int enter_vector_usercopy(void *dst, void *src, size_t n); +#endif /* CONFIG_MMU */ + void xor_regs_2_(unsigned long bytes, unsigned long *__restrict p1, const unsigned long *__restrict p2); void xor_regs_3_(unsigned long bytes, unsigned long *__restrict p1, diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile index 494f9cd1a00c..c8a6787d5827 100644 --- a/arch/riscv/lib/Makefile +++ b/arch/riscv/lib/Makefile @@ -6,9 +6,13 @@ lib-y += memmove.o lib-y += strcmp.o lib-y += strlen.o lib-y += strncmp.o -lib-$(CONFIG_MMU) += uaccess.o +ifeq ($(CONFIG_MMU), y) +lib-y += uaccess.o +lib-$(CONFIG_RISCV_ISA_V) += uaccess_vector.o +endif lib-$(CONFIG_64BIT) += tishift.o lib-$(CONFIG_RISCV_ISA_ZICBOZ) += clear_page.o obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o lib-$(CONFIG_RISCV_ISA_V) += xor.o +lib-$(CONFIG_RISCV_ISA_V) += riscv_v_helpers.o diff --git a/arch/riscv/lib/riscv_v_helpers.c b/arch/riscv/lib/riscv_v_helpers.c new file mode 100644 index 000000000000..be38a93cedae --- /dev/null +++ b/arch/riscv/lib/riscv_v_helpers.c @@ -0,0 +1,45 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2023 SiFive + * Author: Andy Chiu <andy.chiu@sifive.com> + */ +#include <linux/linkage.h> +#include <asm/asm.h> + +#include <asm/vector.h> +#include <asm/simd.h> + +#ifdef CONFIG_MMU +#include <asm/asm-prototypes.h> +#endif + +#ifdef CONFIG_MMU +size_t riscv_v_usercopy_threshold = CONFIG_RISCV_ISA_V_UCOPY_THRESHOLD; +int __asm_vector_usercopy(void *dst, void *src, size_t n); +int fallback_scalar_usercopy(void *dst, void *src, size_t n); +asmlinkage int enter_vector_usercopy(void *dst, void *src, size_t n) +{ + size_t remain, copied; + + /* skip has_vector() check because it has been done by the asm */ + if (!may_use_simd()) + goto fallback; + + kernel_vector_begin(); + remain = __asm_vector_usercopy(dst, src, n); + kernel_vector_end(); + + if (remain) { + copied = n - remain; + dst += copied; + src += copied; + n = remain; + goto fallback; + } + + return remain; + +fallback: + return fallback_scalar_usercopy(dst, src, n); +} +#endif diff --git a/arch/riscv/lib/uaccess.S b/arch/riscv/lib/uaccess.S index 3ab438f30d13..a1e4a3c42925 100644 --- a/arch/riscv/lib/uaccess.S +++ b/arch/riscv/lib/uaccess.S @@ -3,6 +3,8 @@ #include <asm/asm.h> #include <asm/asm-extable.h> #include <asm/csr.h> +#include <asm/hwcap.h> +#include <asm/alternative-macros.h> .macro fixup op reg addr lbl 100: @@ -11,6 +13,13 @@ .endm SYM_FUNC_START(__asm_copy_to_user) +#ifdef CONFIG_RISCV_ISA_V + ALTERNATIVE("j fallback_scalar_usercopy", "nop", 0, RISCV_ISA_EXT_v, CONFIG_RISCV_ISA_V) + REG_L t0, riscv_v_usercopy_threshold + bltu a2, t0, fallback_scalar_usercopy + tail enter_vector_usercopy +#endif +SYM_FUNC_START(fallback_scalar_usercopy) /* Enable access to user memory */ li t6, SR_SUM @@ -181,6 +190,7 @@ SYM_FUNC_START(__asm_copy_to_user) sub a0, t5, a0 ret SYM_FUNC_END(__asm_copy_to_user) +SYM_FUNC_END(fallback_scalar_usercopy) EXPORT_SYMBOL(__asm_copy_to_user) SYM_FUNC_ALIAS(__asm_copy_from_user, __asm_copy_to_user) EXPORT_SYMBOL(__asm_copy_from_user) diff --git a/arch/riscv/lib/uaccess_vector.S b/arch/riscv/lib/uaccess_vector.S new file mode 100644 index 000000000000..51ab5588e9ff --- /dev/null +++ b/arch/riscv/lib/uaccess_vector.S @@ -0,0 +1,53 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#include <linux/linkage.h> +#include <asm-generic/export.h> +#include <asm/asm.h> +#include <asm/asm-extable.h> +#include <asm/csr.h> + +#define pDst a0 +#define pSrc a1 +#define iNum a2 + +#define iVL a3 + +#define ELEM_LMUL_SETTING m8 +#define vData v0 + + .macro fixup op reg addr lbl +100: + \op \reg, \addr + _asm_extable 100b, \lbl + .endm + +SYM_FUNC_START(__asm_vector_usercopy) + /* Enable access to user memory */ + li t6, SR_SUM + csrs CSR_STATUS, t6 + +loop: + vsetvli iVL, iNum, e8, ELEM_LMUL_SETTING, ta, ma + fixup vle8.v vData, (pSrc), 10f + sub iNum, iNum, iVL + add pSrc, pSrc, iVL + fixup vse8.v vData, (pDst), 11f + add pDst, pDst, iVL + bnez iNum, loop + + /* Exception fixup for vector load is shared with normal exit */ +10: + /* Disable access to user memory */ + csrc CSR_STATUS, t6 + mv a0, iNum + ret + + /* Exception fixup code for vector store. */ +11: + /* Undo the subtraction after vle8.v */ + add iNum, iNum, iVL + /* Make sure the scalar fallback skip already processed bytes */ + csrr t2, CSR_VSTART + sub iNum, iNum, t2 + j 10b +SYM_FUNC_END(__asm_vector_usercopy) |